Prosthetic heart valves are used for replacement of defective natural valves in the human heart, being emplaced by open heart surgical procedures. These devices have given thousands of patients a new lease on life, granting them an increased life span, with greater vigor and health, due to the improved blood circulation provided by the prosthetic heart valve.
Some of the most advanced models of prosthetic heart valves are coated with isotrophic, pyrolytic carbon, or a similar material, for the purpose of reducing to an absolute minimum the possibility of the formation of thromboemboli on the heart valve. Such thromboemboli, or blood clots, when they do form, can have fatal consequences to the patient.
Because of the use of the extremely brittle pyrolytic carbon coatings, and because of the general delicate construction of the heart valve, and the absolute requirement that the valve must not be bent or jolted in any way, the design of a shipping package for heart valves is a matter of critical concern.
The package must provide protection from damage by dropping or other severe jolts with an extremely high degree of reliability. The package must also protect the fragile closure member retention struts of the valve from bending during opening or closing of the package. Furthermore, it is preferable for the valve to be gas or stem sterilizable without opening the package, to avoid any possibility of damage to the valve.
One commercial package which is an attempted solution to the above requirements includes a pair of package sections with cylindrical mating portions having spaced detent members, so that the mating portions can be attached together by approximately a 1/8th turn rotation of the two package sections. One of the package sections carries a resilient pad, and the heart valve is pressed against the pad by the outer end of the other package section, for protection of the valve.
One disadvantage of the above arrangement is that, as the two package sections are relatively rotated to free the cooperating detent means on each package section for opening, a frictional torque is directly imparted from the rotating package sections to the struts of the heart valve. In certain undesirable circumstances, this may cause a slight degree of bending in the struts. Such bending could cause the movable closure member of the heart valve to bind and fail to open and close regularly and easily.
In accordance with this invention, an improved heart valve package is provided in which the above disadvantage is avoided, and in which improved protection can be provided to heart valves against rough handling in transit and the like.